DAVE'S - YAMAHA FZR250
1989 model 2KR with EXUP
This bike is 250cc and fitted with what YAMAHA calls EXUP (EXhaust Ultimate Power). It consists of a servo
motor driven valve which is fitted in the exhaust system where the four pipes join into one under the gearbox.
What this does is to close off at low revs to increase the low exhaust back pressure caused by the wild valve timing.
This pressure actually pushes back into cylinders when the exhaust valves first open, increasing downward force on the
pistons, increasing torque at the back wheel at low revs.
The valve progressively starts opening from 3000 rpm to fully open at 8000rpm. The engine therefore performs
usefully between 3000 to 17000rpm.
Engine - 250cc 4 cylinder DOHC 16 valve water-cooled
Power - 45hp at 16000rpm
Torque - 2.5kgfm at 12,000rpm
Full transistor type battery ignition by digital ignition system
Carbs - 4 downdraught MIKUNI BDST28
Frame - steel although during late'89 changed to aluminium (3LN model)
Top speed - 175-180kph
Acceleration - 0-100kph reportedly 5.5seconds
1/4 mile reportedly 14.5 sec
Lean angle - 52deg.
Fairings and tank cover removed for service Air box minus the filter
Recommended tyre sizes